Percutaneous laparoscopic cholecystectomy instrument

ABSTRACT

An instrument for performing a percutaneous laparoscopic cholecystectomy includes a generally rigid, tubular body with a proximal end, a distal end and a lumen extending between these two ends and with a pair of bipolar electrodes projecting from the distal end of the tubular body and a handle member affixed to its proximal end. The outside diameter of the tubular body is sufficiently small that it can readily pass through a cannula inserted through a puncture made through the abdominal wall. A pair of conductors, connected at one end to the bipolar electrodes and at their other end to a source of radio frequency voltage, extend through the tube&#39;s lumen and a handle. Moreover, a fluid port may be formed through the handle so as to be in fluid communication with the lumen of the tube whereby fluids may be perfused through the instrument during its use or a suction may be applied to the proximal port for aspirating the surgical site. In one embodiment of the invention, the bipolar electrodes may be formed as conductive traces extending along the peripheral edges of a thin ceramic blade. In an alternative arrangement, the bipolar electrodes comprise first and second closley space J-spaced conductive hook members.

This is a divisional of copending application Ser. No. 07/516,740, filedon Apr. 30, 1990, now U.S. Pat. No. 5,071,419.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to electrosurgical instruments, andmore particularly to a bipolar electrosurgical cutting instrumentspecifically designed for use in the performance of percutaneouslaparoscopic cholecystectomy procedures.

2. Discussion of the Prior Art

The conventional treatment for a diseased gallbladder has been a totalcholecystectomy involving cutting a fairly large incision through theabdominal wall and, using a scalpel, to dissect the gallbladder from itsbed and to cut the cystic artery and cystic duct to thereby release theorgan and allow it to be extracted through the incision. According toNational Inpatient Profile, Healthcare Knowledge Systems, Ann Arbor,Mich., 1989:360, the average postoperative stay following gallbladderremoval surgery of this type in 1988, on a nationwide basis, was 6.1days and full recovery to normal activities required four to six weeksrecuperation.

A relatively new procedure referred to as "laparoscopic lasercholecystectomy" has been devised and it is significantly less invasivethan the heretofore conventional approach for gallbladder removal.Rather than working through a major incision in the abdominal wall, afirst small puncture would is made in the umbilicus. A needle isinserted and a pneumoperitoneum is established with CO₂ gas to distendthe abdomen. Next, a trocar and cannula are inserted through theumbilical incision and following removal of the trocar, a 10 mm, 0°diagnostic laparoscope is inserted. Rather than direct visualizationthrough the laparoscope, the scene may be viewed on a CRT screen.

Upon proper observation of the peritoneal cavity, three additional stabincisions are made at predetermined locations and cannulas are inserted.Two of the cannulas may be 5 mm in diameter and the other, 11 mm. Thelumens in the cannulas are sufficiently large to permit surgicalinstruments to be inserted therethrough, the instruments including agrasping forceps, a clip applier for ligating the cystic duct and cysticartery and a microscissors. A flexible, fiber-optic rod coupled to theoutput of a laser is used to effect hemostatic cutting and vaporization.

While non-contact positioning of the laser fiber may be used forcoagulation if hemorrhage occurs, in the event that the bleeder islarger than can be controlled with the laser in its non-contact mode,monopolar cautery is used, with the electrosurgical instrument beinginserted through one of the cannulas.

The percutaneous laparoscopic cholecystectomy procedure allows totalremoval of the gallbladder through the larger cannula and following thesurgery, a single stitch in the umbilicus and the use of sterileadhesive strips for closing the other three wounds is all that isrequired. Using this procedure, the hospital stay has been reduced toless than one day and the period for total recovery and resumption ofnormal activities is reduced to about four days. Moreover, scarring isminimal.

OBJECTS

The present invention is directed to a bipolar electrosurgicalinstrument which is specifically designed to be insertable through acannula for use in dissection of the gallbladder from the internalorgans to which it attaches and which may also be used for coagulatingand cauterizing as the need arises during the laparoscopiccholecystectomy procedure. Thus, the more expensive laser surgicalinstrument can be dispensed with and replaced with a disposable low-costsubstitute.

It is accordingly a principal object of the present invention to providean improved instrument for carrying out laparoscopic surgical procedureswith the abdominal cavity.

Another object of the invention is to provide an improvedelectrosurgical instrument for performing laparoscopic cholecystectomy.

Yet another object of the invention is to provide a bipolarelectrosurgical instrument allowing better control over the locationwhere cutting is intended than can be achieved with monopolarelectrosurgical instruments.

SUMMARY OF THE INVENTION

The foregoing features, objects and advantages of the present inventionare attained by providing an electrosurgical instrument comprising agenerally rigid tube having a proximal end, a distal end and a lumenextending from the proximal end to the distal end where the outsidediameter of the tube is sufficiently small to permit it to be passedthrough a cannula percutaneously positioned through the abdominal wall.The length of the rigid tube is sufficient to permit bipolar electrodesaffixed to the distal end thereof to reach the internal organ to besurgically treated when the instrument is inserted through the cannula.The bipolar electrodes are spaced from one another by a predeterminedsmall gap and first and second conductors, each being insulated from theother are extended through the lumen of the rigid tube to connect to thebipolar electrodes. A molded plastic hub is affixed to the proximal endof the rigid tube and associated with the hub are electrical connectormeans especially adapted to permit a source of RF power to be appliedvia the insulated conductors to the bipolar electrodes.

In a first embodiment of the invention, the bipolar electrodes compriseprinted traces of a conductive material formed along the peripheral edgeof an insulating substrate so that the gap comprises the thicknessdimension of the substrate. In an alternative embodiment, the electrodescomprise two separate J-shaped conductive wire hooks which projectoutwardly from the distal end of the rigid tube in a side-by-siderelationship and which are suitably spaced by a ceramic insulatorcoupled between the free ends of the hooks. This latter arrangementaffords the ability of the surgeon to apply traction to the organ beingdissected as RF power is applied to create an arc between the spacedelectrodes, the arc being used to effect the cutting. The application oflower power can be used to supply the requisite heat energy forelectrocautery for coagulation.

DESCRIPTION OF THE DRAWINGS

The foregoing features, objects and advantages of the invention willbecome apparent to those skilled in the art from the following detaileddescription of a preferred embodiment, especially when considered inconjunction with the accompanying in which like numerals in the severalviews refer to corresponding parts.

FIG. 1 is a partially sectioned, side elevation of a bipolar surgicalinstrument configured in accordance with a first embodiment of theinvention.

FIG. 2 is a distal end view of the instrument of FIG. 1;

FIG. 3 is a partially sectioned, side elevational view of a secondembodiment of the invention; and

FIG. 4 is a distal end view of the instrument of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring first to FIG. 1, there is indicated generally by numeral 10 anelectrosurgical instrument specifically designed for use in percutaneouslaparoscopic cholecystectomy surgical procedures. It is seen to comprisean elongated, rigid tubular member 12 which may be formed from a varietyof materials including plastics and metals, with stainless steel perhapsbeing preferred. The tube 12, if fabricated from stainless steel, maycomprise six gauge tubular stock having an outside diameter of 0.205inches and an internal diameter of 0.173 inches. Moreover, it ispreferably blackened over its surface so as to be non-light reflective.The tube 12 has a proximal end 14, a distal end 16 and a lumen 18extending the entire length thereof.

Fitted into the distal end 16 of the rigid tube 12 is a plug member 20(FIG. 2) which may be formed from a high temperature plastic, such asmedical grade polysulfone or a ceramic. The plug 20 includes a narrowslot 22 for receiving the proximal end of an electrosurgical blade 24and a pair of apertures 26 and 28, the purpose of which will bedescribed hereinbelow.

The blade 24 preferably comprises a thin ceramic substrate 30 having apattern of conductive traces as at 32 screened thereon. Ceramics, suchas aluminum nitride and silicon nitride, have proved to be useful inthis application. Specifically, the conductive traces extend around theperimeter of the substrate 30 on opposed side surfaces thereof and arespaced from one another by the thickness dimension of the substrate.This thickness dimension may, typically, be 0.025 inches, but nolimitation to that particular dimension is intended. High temperatureepoxy may be used to tightly secure the blade 24 in the slot formed inthe plug 20 and fastened to the distal end of the rigid tube 12.

With continued reference to FIG. 1, it can be seen that there is affixedto the proximal end 14 of the tube 12 a molded plastic hub 36 having abore 38 formed longitudinally therethrough into which the proximal endportion 14 of the tube 12 is inserted and adhesively bonded.Communicating with the bore 38 is a side port 40 in the form of atubular flexible reinforcement or strain relief member through which apair of insulated conductors 42 and 44 leading to an electrosurgicalgenerator 46 extend. (The electrosurgical generator is preferably of thetype described in the Stasz U.S. Pat. No. 4,903,696. The conductors passthrough the lumen 18 of the rigid tube 12 and are individually connectedto the conductive traces 32 formed on the opposed side surfaces of theblade substrate 30.

Fitted into the proximal end of the hub 36 is a molded plastic plug 48into which is fitted a pair of tubular barb couplers 50 and 52. The barbcoupler 50 is in fluid communication with the bore 38 and, hence, thelumen 18 of the tube 12. When a source of vacuum is joined to the barbcoupler 50, via appropriate tubing, fluids can be aspirated through thedistal bore or port 26 formed in the plug 20.

A tube 54 is secured to the distal end of the barb coupler 52 and thattube 54 extends through the bore 38 and the lumen 18, reaching thedistal port 28 in the plug 20. The barb coupler 52 is adapted to becoupled to a further tube (not shown) leading to a source of flushingliquid, e.g., saline, which allows the flushing liquid to be perfusedthrough the instrument and out its distal port 28.

In use, the instrument of FIG. 1 will have its tubular portion 12inserted through the lumen of a cannula which extends through a punctureformed in the abdominal wall. While viewing the surgical site, via alaparoscope, the surgeon may cause the RF power generated by theelectrosurgical generator 46 to be applied across the gap defined by thethickness of the substrate 30 such that when tissue to be dissected iscontacted by the blade, an arc will be developed across the gapsufficient to effect cutting. When blood or other body fluids obscurethe laparoscopic view of the surgical site, a flushing liquid can beinjected through the coupler 52 and through the tube 54 to exit the port28 while a vacuum is applied, via barbed coupler 50, to allow theflushing liquid and blood to be removed. When it is desired tocoagulate, the same instrument may be used, but with a lower powersetting of the electrosurgical generator 46.

The length of the tubular member 12 is made sufficient to allow theblade 24 to reach the appropriate location within the abdomen when theinstrument is inserted through its cannula. The hub or handle member 36permits the instrument to be readily gripped to facilitate manipulationof the cutting blade 24 relative to the tissue to be dissected.

Referring next to FIGS. 3 and 4, an alternative embodiment of thepresent invention will now be explained. The embodiment of FIGS. 3 and 4differs from that of FIGS. 1 and 2 principally in the configuration ofthe distal plug and the electrode structures used in each. In thearrangement of FIG. 3, rather than including a slot as at 22 in FIG. 2,the plug 56 includes a pair of closely spaced apertures 58 and 60through which J-shaped hook electrodes 62 and 64 project. That is tosay, the electrodes are formed of wire and the shank of the hookelectrode 62 passes through an aperture or bore 58 while the shank ofthe hook electrode 64 fits through the bore 60 in the plug 56. Theelongated conductors 42 and 44 individually connect to the proximal endsof the hook electrodes 62 and 64 within the confines of the lumen 18 ofthe tube 12.

A preferred spacing for the gap, g, between the electrodes 62 and 64 maybe 0.015 inches and can be maintained by utilizing a rigid ceramicspacer bar as at 66 positioned a short predetermined distance(0.020-0.030 inches) from the free ends of the hook electrode 62 and 64The electrodes themselves may comprise 0.014 wires. Using this approach,the portions of the electrodes 62 and 64 extending beyond the spacer 66can be used to initiate cutting when made to pierce into the tissue tobe dissected. The rounded end portions of the hook electrodes can alsobe made to abut tissue so as to cut, on-end, similar to anelectrosurgical blade. If blade-like cutting is required, the contactingof the outer curved portion of the hook loop with the tissue is found toproduce similar results. Because of the manner in which the electrodewires are bent as a hook, the instrument can be used to apply tractionto the tissue as it is being cut. That is to say, the connective tissuemay be hooked and put under tension while being cut off. The pullingmotion is somewhat easier to control through a laparoscope or cannulathan a side-to-side motion which the blade utilizes. This is especiallyadvantageous when it becomes necessary to lift or reposition thegallbladder or other organ during the cutting process.

As with the embodiment of FIGS. 1 and 2, the plug 56 includes anaspiration port 68 and a flushing port 70.

This invention has been described herein in considerable detail in orderto comply with the Patent Statutes and to provide those skilled in theart with the information needed to apply the novel principles and toconstruct and use such specialized components as are required. However,it is to be understood that the invention can be carried out byspecifically different equipment and devices, and that variousmodifications, both as to the equipment details and operatingprocedures, can be accomplished without departing from the scope of theinvention itself.

What is claimed is:
 1. An electrosurgical instrument for performinglaparoscopic procedures comprising:(a) a generally rigid tube having aproximal end, a distal end, lumen means extending from said proximal endto said distal end for allowing passage of fluids therethrough, saidtube having an outside diameter of a size allowing passage through acannula and of a length sufficient to reach the internal tissue to beexcised when said tube is inserted through the abdominal wall via saidcannula; (b) a blade member affixed to said distal end of said tube,said blade member comprising a flat insulating substrate having aperipheral edge and first and second major surfaces with a conductivetrace extending along at least a portion of said peripheral edge on saidfirst and second major surfaces, the conductive trace on said firstmajor surface being spaced from the conductive trace on said secondmajor surface by a gap corresponding to the thickness of said flatsubstrate at said portion of said peripheral edge; (c) first and secondconductors insulated from one another and extending through said lumenmeans, said first and second conductors being individually connected atone end to said conductive traces on said first and second majorsurfaces; (d) a hub member affixed to said proximal end of said tube,said hub member including at least one passage in fluid communicationwith said lumen means; and (e) means connected to said first and secondconductors for connecting said first and second conductors to a sourceof RF voltage such that a high intensity field is created in said gapeffective to cut through said tissue.
 2. The electrosurgical instrumentas in claim 1 and further including a second lumen means extending thelength of said tube and said hub member includes a second passage influid communication with said second lumen means.
 3. A bipolarelectrosurgical instrument for performing laparoscopic cholecystectomycomprising:(a) a generally rigid tubular member having a proximal endand a distal end and a first lumen extending from said proximal end tosaid distal end, the outside diameter of said tubular member beingsufficiently small to pass through a cannula; (b) a blade member affixedto said distal end of said tubular member, said blade member comprisinga thin elongated, narrow substrate having a peripheral edge and firstand second major surfaces with a conductive trace extending along atleast a portion of said peripheral edge on said first and second majorsurfaces, the conductive trace on said first major surface being spacedfrom the conductive trace on said second major surface by the thicknessof said thin substrate at said portion of said peripheral edge; (c) ahandle member secured to said proximal end of said rigid tubular member,said handle member including first and second passages communicatingwith said first lumen; (d) conductor means extending through said firstpassage and said lumen for coupling a source of RF voltage across saidconductive traces on said first and second major surfaces; and (e) meansfor coupling a vacuum to said second passage.